#define _CRT_SECURE_NO_WARNINGS 1
#include <stdio.h>
int BinSearch(int a[], int n, int x)
{
	int left = 0, right = n - 1, mid;  //下标从0开始
	while (left <= right)
	{
		mid = (left + right) / 2;
		printf("[%d,%d][%d]\n", left, right, mid);
		if (a[mid] > x)
			right = mid - 1;
		else if (a[mid] < x)
			left = mid + 1;
		else
			return mid;
	}
	return -1;
}

int main()
{
	int n, x, t, flag = 1, a[1000];
	scanf("%d %d", &n, &x);

	for (int i = 0; i < n; i++)
		scanf("%d", &a[i]);

	for (int i = 0; i < n - 1; i++)
	{
		if (a[i] >= a[i + 1])
		{
			printf("Invalid Value");
			flag = 0;
			break;  //注意这里的break 
		}
	}

	if (flag)
	{
		t = BinSearch(a, n, x);
		if (t == -1)
			printf("Not Found");
		else
			printf("%d", t);
	}
	return 0;
}